The Grateful Dead's most legendary concert is finally getting an official release after years of being bootlegged among Deadheads.

Jerry Garcia, Donna Jean Godchaux, Keith Godchaux, Mickey Hart, Bill Kreutzmann, Phil Lesh and Bob Weir performed at Cornell University's Barton Hall on May 8, 1977. Recordings have been shared online by fans who called it "the best Grateful Dead show of all time" and long praised its sound quality.

"The Grateful Dead just touched a nerve, and it's still relevant in many ways today," Hart told the AP in 2012, when the tape was added to the National Recording Registry by the Library of Congress. "It's American-based music, but the combination of it, I guess, was the chemical that ignited, the energy that ignited the spirit of the people for many generations."

The epic, full-length show will get its first commercial release on May 5th in celebration of its 40th anniversary, as part of an 11-disc box set called "Get Shown the Light." The jam rock band teased the release by posting their psychedelic, 14-minute cover of "Morning Dew" from the Ithaca performance on SoundCloud:

David Lemieux, Grateful Dead archivist and "Get Shown the Light" producer, told Rolling Stone: "It's long been a dream of everyone in the Grateful Dead organization to release the definitive version of Cornell, drawn from the master tapes, and we're as thrilled as the fans are that this show is finally being released."

According to the magazine, the Cornell show was part of the Dead's "Terrapin Station" tour, captured by live recording engineer Betty Cantor-Jackson. The box set also includes previously unreleased recordings from her soundboard tapes, known as the "Betty Boards," of other 1977 tour stops with highlights like "Promised Land" in New Haven, Connecticut and "Uncle John's Band" in Buffalo, New York.

The box set, limited to 15,000 individually numbered copies, is available to pre-order at dead.net. It also features the book "Cornell '77: The Music, the Myth and the Legend of the Grateful Dead's Concert at Barton Hall," and an essay by Dead scholar Nicholas G. Meriwether.

The Cornell set will also be available separately in three-CD, five-LP, digital download, and streaming formats beginning May 5.